Head to head · Shipping rates · October 2026 research run
Karrio vs ShipStation API
ShipStation API scores 59.3 (C) on agent readiness against Karrio's 48.7 (D), and leads in 4 of 7 scored categories. Karrio leads on reliability and security & auth. Both do shipping rates.
Which one, for what
Karrio D
Good for A team that wants to host its own multi-carrier API with its own carrier contracts and can maintain a Django and PostgreSQL stack.
Ahead on
- Reliability, 76 against 64
- Security & auth, 44 against 32
Also in its favour
- Open source
Watch for
No release since 2026.1.32 on 23 June 2026, 107 days before this check, and fix pull requests opened in September 2026 were still open
Good for An agent working inside a merchant's existing ShipStation account (orders, batches, inventory, labels), or a developer who wants a free sandbox through the ShipStation API plans.
Ahead on
- Schema & documentation, 83 against 68
- Agent ergonomics, 64 against 57
- Maintenance & community, 73 against 29
- Transparency & trust, 64 against 56
Also in its favour
- A hosted endpoint, with nothing to install
- No incidents deducted, where Karrio loses 7 points for them
Watch for
One API key with full account access. No scopes, read-only keys or approval step before a label is bought
Score by category
| Category | Weight this run | Karrio | ShipStation API | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 76 | 64 | Karrio +12 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 68 | 83 | ShipStation API +15 |
| Agent ergonomics | 13%16.2 | 57 | 64 | ShipStation API +7 |
| Security & auth | 14%17.5 | 44 | 32 | Karrio +12 |
| Payments & pricing | 10%12.5 | 40 | 40 | even |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 29 | 73 | ShipStation API +44 |
| Transparency & trust | 7%8.8 | 56 | 64 | ShipStation API +8 |
| Negative events | ≤15 | -7 | 0 | |
| Total | 48.7 · D | 59.3 · C |
Facts side by side
| Fact | Karrio | ShipStation API |
|---|---|---|
| Kind | HTTP API | HTTP API |
| Vendor | Karrio, Inc. | Auctane LLC d/b/a ShipStation |
| Hosted endpoint | no (local only) | https://api.shipstation.com/v2 |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | LGPL-3.0 for the server, SDK and modules. Code under ee/ is under the Karrio Enterprise licence and needs a subscription for production use. The MCP package in packages/mcp is Apache-2.0 | Proprietary service under ShipStation's terms of service. The v2 OpenAPI file is marked MIT and the SDKs on GitHub are Apache 2.0 |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| Last release | 2026-06-23 | 2026-10-01 |
| Terms last updated | 2025-04-08 | no date given |
| Privacy policy last updated | 2025-04-08 | 2026-03-18 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | yes |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | 799 stars, 338 PyPI/wk | 6.8k npm/wk |
Verdicts
Karrio
A current OpenAPI 3.0.3 contract with 65 paths, a free LGPL-3.0 server and 30 carrier connectors suit a team that hosts it. The last release was 23 June 2026, the @karrio/mcp package the docs install is absent from npm, and api.karrio.io didn't resolve on 8 October 2026.
ShipStation API
A public OpenAPI 3.1 contract with 173 operations, Markdown docs for agents and a free ShipStation API plan with a sandbox make a first rate quote or test label reachable without a contract. One API key carries full account access, with no scopes, read-only mode or idempotency keys on label purchases.
Before you call either
Karrio
- Run your own instance with Docker Compose and call it at
http://localhost:5002. Don't rely onapi.karrio.io, which didn't resolve on 8 October 2026 - Don't run
npx karrio-mcpornpx -y @karrio/mcp. Neither name is published on npm, so build the server frompackages/mcpin the repository - Change the default
admin@example.comanddemologin before the instance is reachable, and upgrade to 2026.1.32 or later so passwords aren't stored as MD5 - Don't blind-retry
POST /v1/shipmentswith aserviceset orPOST /v1/shipments/{id}/purchase. Fetch the shipment and check its status first, since no idempotency key exists - Use a test-mode API key while building. Send it as the HTTP Basic username or as
Authorization: Token key_...
ShipStation API
- Send the key in an
API-Keyheader to https://api.shipstation.com/v2. A key that startsTEST_runs in the sandbox on the same host - Call GET /v2/carriers first. Rate and label calls need
carrier_idsor acarrier_idand aservice_codefrom that account - Don't blindly retry POST /v2/labels after a timeout. List labels first, then void a duplicate with PUT /v2/labels/{label_id}/void
- Check the
errorsarray on 2XX responses too, and readerror_sourceto tell a carrier fault from a ShipStation one - On a platform (Standard or Premium) key every label is real and charged. Ask the owner before buying, and void test labels at once
Questions
Which is better for AI agents, Karrio or ShipStation API?
ShipStation API scores 59.3 (C) on agent readiness against Karrio's 48.7 (D), and leads in 4 of 7 scored categories. Karrio leads on reliability and security & auth.
Do Karrio and ShipStation API need an API key?
Both need an API key.
Can an agent call Karrio and ShipStation API without installing anything?
No hosted endpoint is listed for Karrio. ShipStation API has a hosted endpoint at https://api.shipstation.com/v2.
Are Karrio and ShipStation API open source?
Karrio is open source (LGPL-3.0 for the server, SDK and modules. Code under `ee/` is under the Karrio Enterprise licence and needs a subscription for production use. The MCP package in `packages/mcp` is Apache-2.0). No open-source release is listed for ShipStation API.
Other comparisons with Karrio or ShipStation API
Machine-readable
- This page as Markdown
/compare/karrio-vs-shipstation.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/karrio.json·/api/v1/tools/shipstation.json - From a terminal
anchor compare karrio shipstation(the CLI) - Over MCP
compare_tools {"a": "karrio", "b": "shipstation"}at/mcp, no key